DE112008002055T5 - Channel-aware multi-user MIMO scheme unified with single-user closed-loop MIMO - Google Patents

Abstract

Method, comprising:
in uplink transmission, receiving rank 1 channel quality indicator values from one or more subscriber stations, the channel quality indicator values being based, at least in part, on channel information;
in an uplink transmission, receiving two or more vectors from the one or more subscriber stations;
Determining which of the one or more subscriber stations has a best rank-1 channel quality indicator value;
Determining a beamforming matrix based at least in part on the two or more vectors received from the subscriber station with the best rank-1 channel quality indicator value; and
in a downlink transmission, using the beamforming matrix corresponding to the subscriber station with the best ranked 1-channel quality indicator, to the one or more subscriber stations.

Description

BACKGROUND

Multiple User - multiple-input, Multiple-output (MU-MIMO) schemes have always been used in recent years More attention has been paid to MU-MIMO for multi-user diversity as well for spatial diversity can provide. The capacity from MU-MIMO can be much higher as a single-user MIMO (single-user MIMO (SU-MIMO)), specifically for example, if the antenna configuration is asymmetric, for Example in a 4 × 2 arrangement or a 2 × 1 arrangement, be. An asymmetric configuration can occur when a base station (base station (BS)) a larger number of Transmit (Tx) antennas as the number of receive (receive (Rx)) - antennas at the subscriber station (SS) or in a channel state with high correlation. MU-MIMO differs from SU-MIMO in that MU-MIMO with sending of transmission streams for several User can be connected in a sending function unit.

DESCRIPTION OF THE FIGURES

Of the claimed subject matter is in the summary of the description particularly stressed and clearly stressed. Named object however, by reference to the following detailed Description in conjunction with the attached drawings, in which:

1 shows a block diagram of a MU-MIMO system according to one or more embodiments;

2 12 shows a diagram of a multi-stream, channel-aware MU-MIMO transmission scheme according to one or more embodiments;

3 Fig. 12 shows a diagram of a MU-MIMO transmission scheme using feedback (channel quality indicator and vector (CQI / V)) without downsampling according to one or more embodiments;

4 Figure 12 shows a diagram of a MU-MIMO transmission scheme using feedback of a channel quality indicator and vector (CQI / V) with downsampling according to one or more embodiments; and

5 FIG. 3 shows a flow diagram of a method for merging a multi-user MIMO scheme with a single-user MIMO scheme, according to one or more embodiments.

It becomes understandable be that sake of simplicity and / or clarity of illustration Elements shown in the figures are not necessarily to scale are drawn. For example, you can the dimensions of some of the elements in relation to other elements for the sake of clarity, exaggerated be shown. If considered correctly, reference numbers are further have been repeated in the figures to corresponding and / or analogous elements specify.

DETAILED DESCRIPTION

In the following detailed Description, numerous special details are set forth for a comprehensive understanding of the claimed subject matter. For professionals in the field will be understood, however be that the claimed object without these special details in the practice can be implemented. In other examples are general known methods, procedures, components and / or circuits not described in detail.

In the following description and / or claims, the terms "coupled" and / or "connected", along with their derivatives, may be used. In particular embodiments, "connected" may be used to indicate that two or more elements are in direct physical and / or electrical contact with each other. "Coupled" may mean that two or more elements are in direct physical and / or electrical contact. But "coupled" can also mean that two or more elements are not in direct contact with each other but still work together and / or interact with each other unchanged. For example, "coupled" may mean that two or more elements are not in contact with each other but are indirectly connected to each other via another element or elements. Finally, the terms "on,""overlying," and "over," may be used in the following description and in the claims. "Up,""overlying" and "over" can be used to indicate that two or more elements are in direct physical contact with each other. However, "over" may also mean that two or more elements are not in direct contact with each other. For example, "over" may mean that one element is disposed over another element but can not contact one another and another element or elements may be present between the two elements. In addition, the term "and / or" may mean "or" meaning "exclusive or" meaning "one (1)" meaning "some but not all" meaning "none" mean and / or "both," although the scope of the claimed subject matter is not limited in this regard. In the following description and / or claims, the terms "comprising" and "including" together with their derivatives may be used as synonyms for each other and so provided.

With reference to 1 A block diagram of a MU-MIMO system according to one or more embodiments will now be discussed. As in 1 shown is the MIMO system 100 a base station (Base Station (BS)) 110 and one or more Subscriber Stations (SS) 114 comprising a first subscriber station (SS ₁ ), a second subscriber station (SS ₂ ), up to N subscriber stations (SS _N ), one or more of the subscriber stations 114 with the base station 110 can communicate wirelessly. In such a MIMO system 100 can the base station 110 several antennas 112 include and can the respective subscriber stations 114 equally one or more antenna (s) 116 . 118 and or 120 exhibit. It should be known that the number of one or more subscriber stations 114 may have their own number of antennas, for example when the number of antennas 116 the first subscriber station SS ₁ other than the number of antennas 118 of the second subscriber station SS ₂ , both of which may be different than the number of antennas of an Nth subscriber station SS _N. Similarly, one or more of the subscriber stations 114 a different number of antennas than the number of antennas 112 the base station, although in some cases one or more of the base stations 110 and one or more of the subscriber stations 114 may have the same number of antennas, and the scope of the claimed subject matter is not limited in this respect. It should also be noted that the model is base station 110 and subscriber station 114 , this in 1 only one example of an arrangement of the MIMO system is shown 100 and, in one or more alternative embodiments, the base station 110 even a subscriber station 114 may be and / or one or more of the subscriber stations 114 with another or more of the subscriber stations 114 can communicate directly, for example in an ad hoc network arrangement or the like, and the scope of the claimed subject matter is not limited in this respect.

In one or more embodiments, the communication between the base station 110 and one or more of the subscriber stations 114 associated with precoding, spatial multiplexing and / or diversity encoding, singly or in combination. Furthermore, the base station 110 with one of the subscriber stations 114 communicate directly by sending all their antenna resources to the respective subscriber station 114 For example, to achieve higher data rates, or alternatively, the base station 110 some of their antenna resources to one or more subscriber stations 114 for example, serving a larger number of subscriber stations 114 to optimize. In one or more embodiments, which will be discussed herein, the MIMO system may 100 Implement a channel aware multi-user MIMO (Channel Aware Multi-User MIMO (CA-MU-MIMO)) system. In such a channel aware MIMO system 100 For example, a precoding vector and / or the codebook index may be based, at least in part, on a feedback made by one or more users, such as one or more of the subscriber stations 114 is received, be channel aware (channel aware). In one or more embodiments, Channel Quality Indicators (CQIs) corresponding to selected precoding vectors become the base station 110 for user scheduling (user scheduling) of the subscriber stations 114 in the base station 110 returned. The user time control in the base station 110 may be based on one or more principles, for example, user orthogonality, or the maximization of proportional fairness metric and so forth. In one or more particular embodiment (s), two types of CQIs, for example Rank-1 (Rank-1) and Rank-2 (Rank-2), may be used for MIMO rank / mode adaptation. Interference unaware Rank 1 CQIs can be used to select the precoding vector, and interference-inference rank 2 CQIs can be used for MIMO rank / link / mode adaptation and user selection. By using the same codebook as used in a single-user closed-loop (MIMO) single-user closed-loop scheme, this can be done by the MIMO system 100 Implemented channel-aware MU-MIMO scheme can be unified with a closed single-user MIMO scheme. Such a MU-MIMO scheme will be described with reference to 2 . 3 and 4 discussed in more detail below.

With reference to 2 Now, a diagram of a multi-stream channel aware MU-MIMO transmit scheme will be discussed in accordance with one or more embodiments. In the in 2 shown channel-conscious MU-MIMO scheme 200 can be a broadcasting procedure by the base station 110 can be implemented for multiple streams, such as a 2 × 2 arrangement with two currents, look like this. One should note that the 2 × 2 nomenclature applies to the base station 110 refers to the two antennas for transmission to a subscriber station 114 used, which uses two antennas for receiving. In short, the send procedure may include a channel aware MU-MIMO procedure with CQI and vector return. The subscriber station 114 Can Single Value Decomposition (SVD) of All User Channels in Second to Last Subframe 214 of the i-th frame 212 perform the beamforming vectors for each subscriber station 114 to obtain. Then enter the subscriber stations 114 a rank 1 CQI to the base station 110 back. In addition, each of the subscriber stations 114 their respective two main vectors to the base station 110 hand back. The base station 110 then determines the selected beamforming vectors, which in the 2 × 2 case comprise two vectors, from the subscriber station 114 with the best Rank 1 CQI score. The base station 110 can then in the last subframe 216 of the i-th frame 210 the selected vectors from the subscriber station 114 with the best Rank 1 CQI value to all subscriber stations 114 broadcast. Then, each subscriber station calculates for rank 2 CQI return in the last subframe 216 of the i-th frame 216 the rank 2 CQIs, which in this case may include two rank 2 CQIs, by using those from the base station 110 received broadcast vectors. The subscriber stations 114 can then calculate two CQIs to the base station 110 hand back. Upon receipt, the base station can 110 based on timing criteria and / or MIMO mode / rank according to rank-1 / rank-2 CQIs that the base station 110 from subscriber stations 114 has to identify the pairing users. If the rank 1 mode or the same user is assigned two streams over the same resource block (RB), then the base station may 110 select to use single-user MIMO transmission. Otherwise, multi-user transmission is selected.

In one or more embodiments, a more detailed broadcasting procedure may be for the channel-aware MU-MIMO scheme 200 from 2 look like this. In the second to last subframe 214 of the i-th frame 210 gives each participant station 114 a rank 1 CQI value to the base station 110 for the uplink (UL) transmission of subscriber stations 114 to the base station 110 for the rank adaptation based on the channel information for itself on which the SVD decomposition can be based. In the Rank 1 CQI calculation, there is no interference resulting from the second stream. Each subscriber station thereafter outputs its two main vectors, or beamforming matrix, from their respective SVD decomposition via their own channel matrix to the base station 110 back.

Next, compare the base station 110 in the last subframe 216 of the i-th frame 210 for the downlink (DL) transmission from the base station 110 to the subscriber stations 114 all from each of the subscriber stations 114 received rank-1 CQIs and determines which of the subscriber stations 114 has the best Rank 1 CQI value. The base station 110 can then determine a selected beamforming matrix containing the two main beamforming vectors from the base station 114 with the best rank-1 CQI score. The base station 110 then sends the selected beamforming matrix to all of the subscriber stations 114 in the MIMO system 100 round.

For the subsequent uplink transmission, each of the subscriber stations then calculates the rank 2 CQIs, which may include two rank 2 CQIs in the two stream case, by using the beamforming matrix vectors, in this case two vectors, and then send the two calculated CQIs to the base station 110 back. In one or more embodiments, the rank 2 CQIs may be determined using a minimum mean squared error (MMSE) receiver at the subscriber stations 114 can calculate. Each participant station 114 then returns two rank 2 CQIs to the base station 110 back to the user pairing.

Next, the base station 110 in the first subframe 218 of the (i + 1) th frame 212 , the next frame for the downlink transmission, the paired subscriber stations 114 based on timing criteria for MU-MIMO and / or based on MIMO-mode / rank according to the rank-1 / rank-2 CQIs preceding the subscriber stations 114 received, determine. The base station 110 can then begin to send data by using the precoding vectors as follows. If the value of the rank 1 CQI is greater than the single user rank 2 CQIs and / or the multi-user rank 2 CQIs, the base station selects 110 SU-MIMO Rank 1 mode for data transmission. In this case, the base station 110 a stream with the first vector from the broadcasted beamforming matrix for the selected subscriber station 114 send. This selected subscriber station 114 corresponds to the highest order rank 1 CQI compared to the SU MIMO rank 2 CQIs and / or MU MIMO rank 2 CQIs.

Otherwise, the base station dials 110 in the case that the single user rank 2 CQI is greater than the single user rank 1 CQI and / or the Multi-user rank 2 CQIs is off, the SU-MIMO rank 2 mode for data transfer. In this case, the base station 110 two streams of the two vectors from the broadcast beamforming matrix for the selected subscriber station 114 send. This selected subscriber station 114 corresponds to the highest order SU rank 2 CQIs compared to the SU rank 1 CQI and / or MU rank 2 CQIs.

If none of the above comparisons are valid then the base station will otherwise dial 110 the MU MIMO rank 2 mode for data transmission. In this case, the base station 110 send two streams with the two beamforming vectors from the broadcast beamforming matrix for the selected two different subscriber stations. These two selected subscriber stations 114 will have the most significant MU rank 2 CQIs based on a summation over two different subscriber stations 114 , compared to the SU rank 1 CQI and / or the SU rank 2 CQIs.

In one or more embodiments, the channel-aware MU-MIMO scheme may 200 , this in 2 shown, to a larger number of streams, more than two streams, and a larger number of antenna configurations, for example, a 4 × 2 antenna configuration, in which the base station 110 may have four antennas and the subscriber stations 114 may have two antennas, or a 4 × 4 antenna configuration, where the base station 110 may have four antennas and the subscriber stations 114 four antennas, and so on, can be expanded. In such extensions, the difference may include the number of return beamforming vectors and CQIs used. There will be a corresponding return number for the beamforming vectors and CQIs in the higher number of antennas / number of antennas configuration. For example, in the case of four streams over a 4 × 4 antenna configuration, there will be four beamforming vectors for broadcasting and four CQIs for user pairing for multiple users in the MIMO system 100 give. However, these are merely examples of how multiple streams and / or larger numbers of antennas can be implemented, and the scope of the claimed subject matter is not limited in this respect.

With reference to 3 Now, a diagram of a MU-MIMO transmission scheme will be discussed using return of a channel quality indicator and vector (CQI / V) without downsampling according to one or more embodiments. In the channel-aware MU-MIMO scheme 300 from 3 No downsampling is used at the frame level. In a particular embodiment, the frame size is 5 milliseconds, although the scope of the claimed subject matter is not limited in this respect. As in 3 2, each subscriber station may be shown for each subframe 114 the same content to the base 110 for example, each subscriber station will return 114 return a CQI value based at least in part on the last channel information. Each participant station 114 The two rank-2 CQIs will be based at least in part on the broadcasted two or more beamforming vectors generated by the base station 110 receive and then calculate the rank 2 CQIs to the base station 110 hand back.

In the next subframe becomes the base station 110 two new beamforming vectors from the subscriber stations 114 with the highest-grade rank-1 CQI for broadcasting. The base station 110 will send the data through the selected MIMO mode, either an SU-MIMO mode or a MU-MIMO mode, and use the selected beamforming vector to precode over the data. In one or more embodiments, the entire band return in a subframe may be based, at least in part, on a Best-M algorithm for reducing the feedback overhead. The beamforming vector may also be used in conjunction with the CQI return based at least in part on a Best-M algorithm. Such an embodiment may be implemented via a stream line mode. Each subframe may have the same return overhead, and each subframe may implement switching between an SU-MIMO mode and a MU-MIMO mode, between rank-1 and rank-2, and so on, although the scope of protection of the claimed subject matter is not limited in this regard.

With reference to 4 Now, a diagram of a MU-MIMO transmission scheme using return of a channel quality indicator and vector (CQI / V) with downsampling in accordance with one or more embodiments will now be discussed. In the channel-aware MU-MIMO scheme 400 from 4 Downsampling can be used to return at the frame level. In one or more embodiments, the frame size 5 Milliseconds or more. The MU-MIMO scheme 400 from 4 is essentially similar to the MU-MIMO scheme 300 from 3 in which the difference may include the switching unit or a switching period. Any frame of 5 milliseconds or longer frames greater than 5 milliseconds will return the same content. For example, each subscriber station becomes 114 to return a CQI based, at least in part, on the most recent channel information. Each participant station 114 will calculate two rank 2 CQIs based, at least in part, on the transmitted two beamforming vectors, which will thereafter become the base station 110 be returned.

In the next frame of 5 ms or longer frames larger than 5 ms, the base station becomes 110 select two new beamforming vectors from the subscriber station with the most significant rank 1 CQI for broadcasting. The base station 110 will send the data via the selected MIMO mode, either SU-MIMO or MU-MIMO, and use the selected beamforming vector to precode over the data. Returning over the entire band in a frame of 5 ms or longer frames greater than 5 ms may be based, at least in part, on a Best-M algorithm to reduce the return overhead. The beamforming vector may also be used in conjunction with CQI return based at least in part on a Best-M algorithm. Such a case may be implemented via stream line mode. Each frame of 5 ms or longer frames greater than 5 ms will have the same return overhead, and each frame of 5 ms or longer frames longer than 5 ms may switch between SU-MIMO and MU-MIMO, between rank-1 and rank-2, and so on, although the scope of the claimed subject matter is not limited in this respect.

In one or more embodiments, a channel-aware MU-MIMO scheme may implement timing and / or hybrid automatic repeat request (HARQ) retransmission. User-driven control for channel-aware MU-MIMO may be based on user timing in the base station based at least in part on principles such as user orthogonality or maximizing proportional fairness metric, and so forth. In user control, the base station becomes 110 calculate the PF metric based at least in part on the SU rank 1, SU rank 2 and / or MU rank 2 CQIs and / or based at least in part on criteria to form a MIMO mode for the Select transmission. Then the user pairing can be determined.

For HARQ implemented in a channel aware MU-MIMO scheme, HARQ retransmission could be implemented as an asynchronous mode or a synchronous mode. A non-blanking / blanking (HARQ) mode could be used for a channel-aware MU-MIMO scheme where MU-MIMO will have two streams for transmission, even if the MIMO system 100 undergoes a retransmission. For example, in the case where two data streams are supported, in the case where two streams are transmitted for MU-MIMO, a stream with an error would retransmitted to the next transmission time. The other correct stream would be transmitted with new data at the next transmission time. The pre-coding vectors used for the new data and retransmission could be the latest beam-forming vectors from the MU-MIMO timing controller.

In one or more embodiments of MU-MIMO, mode / rank adaptation may be used to maintain link performance even if the channel is changed. The change mode could be implemented for both flexible and / or semi-static solutions. For the flexible adaptation mode, subscriber stations will return CQI values of all adaptable ranks / modes, and then the base station 110 collect all the information on the mode / rank determination. The change could be implemented on a frame by frame basis. Such a change mechanism may have sufficient performance with greater return overhead. For a semi-static adaptation subscriber stations 114 request an adaptation if a subscriber station 114 a channel change is noticed, and then the base station 110 decide on the needed adaptation. In such an arrangement, the frequency may change relatively slowly, but using a lower return overhead.

In one or more embodiments the channel-aware MU-MIMO scheme downlink transmission for pilot signal measurement and / or Use detection. It can Pilots are implemented for measurement, for example, using a scattered common pilot, a midamble, Reference signals for calculating the MIMO CQI return, such as for example, a channel quality indicator (Channel Quality Indicator (CQI)), Control Sequence Indicator (Control Sequence Indicator (CSI)) and reserve indicator (Power Margin Indicator (PMI)), codebook index, etc. When pilots are used for demodulation, For example, a channel-aware MU-MIMO scheme may have a dedicated, pre-encoded one Pilots for use the data detection to save the pilot overhead, although the scope of the claimed subject matter is not limited in this respect.

With reference to 5 A flow diagram of a method of associating a multi-user MIMO scheme with a single-user MIMO scheme in accordance with one or more embodiments is discussed. The procedure 500 from 5 includes a special order of one SU-MIMO and MU-MIMO schemes, however, the procedure may 500 other orders include and / or more or fewer blocks than in 5 and the scope of the claimed subject matter is not limited in this respect. At block 510 receives a base station 110 Rank 1 CQI scores from one or more participating states 114 that can generally be called a user. At block 512 receives the base station 110 two or more vectors from the respective subscriber stations corresponding to a beamforming matrix codebook. The base station 110 then determines at block 514 which the user has the best Rank 1 CQI value. The base station 110 then select the vectors corresponding to the user with the best Rank 1 CQI value at block 516 , Using the vectors from the user with the best Rank 1 CQI value, the base station transmits 110 the vectors to all the users at block 518 round. The users will then calculate rank 2 CQI values using the broadcast vectors and then return the rank 2 CQI values received at the base station 110 at block 520 be received. The base station 110 then determines user pairing based on at least in part the Rank 2 CQI values at block 522 by comparing the rank 1 and rank 2 values received from the subscriber stations 114 were obtained. When the base station 110 at block 524 determines if a rank 1 CQI value is the best of the CQI values, or if the same user is assigned two or more streams, then the base station selects 110 Single-user MIMO operation. Otherwise, if the base station at block 526 Determining two or more users who have the best rank 2 CQI scores selects the base station 110 Multi-user MIMO operation.

Even though the claimed subject matter is described with a degree of particularity should be recognizable that elements of the same by professionals modified in the field can be without departing from the spirit and / or scope of the claimed subject matter to get. It is assumed that the subject, the one channel-aware multi-user MIMO schema, that with closed Single-user MIMO is unified, and / or many of its associated tools will be understood from the foregoing description, and it will be apparent that numerous changes in the form, construction and / or arrangement of the components thereof can, without from the scope and / or spirit of the claimed subject matter to get or sacrifice all its material benefits, taking the form described hereinbefore is merely exemplary embodiment same and / or further without significant changes thereto. The requirements should such changes include and / or contain.

Summary

A Base station can receive a single-user MIMO scheme with a multi-user MIMO scheme Rank 1 CQI scores from one or more subscriber stations combine. The base station also receives precoding vectors from the Subscriber stations and then determines which of the subscriber stations a best Rank 1 CQI score having. The base station then determines a beamforming matrix to use based at least partially on that of the subscriber station received vectors with the best Rank 1 CQI value. Then send the base station transmits data to the subscriber station using the beamforming matrix, the subscriber station with the best Rank 1 channel quality indicator corresponds to single-user MIMO in one or more streams for Implement subscriber stations, or to the subscriber stations with the best rank 2 channel quality indicators, to implement multi-user MIMO in multiple streams.

Claims (20)

Method, comprising: in an uplink transmission Receive rank-1 channel quality indicator values from one or more subscriber stations, the channel quality indicator values based at least in part on channel information; in a Uplink transmission Receiving two or more vectors from the one or more Subscriber station (s); Determine which of the one or more Subscriber station (s) has a best rank 1 channel quality indicator value; Determine a beamforming (beamforming) matrix based at least for Part on the two or more vectors coming from the subscriber station received the best rank 1 channel quality indicator value were; and Broadcasting in a downlink transmission using the Beamforming Matrix, the subscriber station with the best rank-1-channel quality indicator, at the one or more subscriber stations. The method of claim 1, further comprising: in an uplink transmission, receiving rank 2 channel quality indicator values from the one or more remote terminals; if the rank 1 channel quality indicator value is greater than or greater than the rank 2 channel quality indicator values of individual subscriber stations Rank 2 channel quality indicator values from multiple subscriber stations, then: selecting a single-user multiple-input, multiple-output-rank-1 mode for data transmission; and transmitting a data stream using the ranked 1 vectors for beamforming corresponding to the subscriber station having the best ranked 1 channel quality indicator value. The method of claim 1, further comprising: in an uplink transmission Receive rank 2 channel quality indicator values from the one or more subscriber stations; if a rank 2 channel quality indicator value greater than a rank 1 channel quality indicator value from a single subscriber station or greater than a rank 2 channel quality indicator value from several subscriber stations, then: Select one Single user multiple input, multiple output (multiple output) rank 2 mode for data transmission; and Send of two data streams using the beamforming matrix for the subscriber station with the best rank 2 channel quality indicator score. The method of claim 1, further comprising: in an uplink transmission Receive rank 2 channel quality indicator values from the one or more subscriber stations; if two or more subscriber stations have the best rank 2 channel quality indicator values have, then: Choose a multi-user multiple input, multiple output (multiple output) rank 2 mode for data transmission; and Send of two data streams using the beamforming matrices for the two or more subscriber stations with the best rank 2-channel quality indicator value. Method according to claim 1, characterized in that that the channel quality indicator values at least partially on a singular value decomposition (singular value decompostion). Method according to claim 1, characterized in that that the channel quality indicator values at least in part on an assumption of no interference between two or streams based. Method according to claim 2, characterized in that that said receiving rank-1 channel quality indicator values from one or more subscriber station (s) and said receiving of rank 2 channel quality indicator values from the one or more subscriber stations in each subframe takes place. Method according to claim 2, characterized in that that the rank-1 channel quality indicator values from one or more subscriber stations and said receiving Rank 2 channel quality indicator values from the one or more subscriber stations in each subframe based at least in part on a Best-M calculation, to return (feedback) overhead from reduce the one or more users. An article of manufacture comprising a storage medium with stored commands that result in execution: in an uplink transmission Receive rank-1 channel quality indicator values from one or more subscriber stations, the channel quality indicator values based at least in part on channel information; in a Uplink transmission Receiving two or more vectors from the one or more Subscriber station (s); Determine which of the one or more Subscriber station (s) has a best rank 1 channel quality indicator value; Determine a beamforming matrix based at least in part on the two or more vectors from the subscriber station with the best rank-1 channel quality indicator value were received; and in a downlink transmission and broadcasting the beamforming matrix that the subscriber station with the best Rank-1 channel quality indicator corresponds to the one or more subscriber stations. An article of manufacture according to claim 9, characterized that the commands at execution have as a consequence: in an uplink transmission, receiving rank 2 channel quality indicator values from the one or more subscribers' stations; if a rank 1 channel quality indicator value greater than the rank 2 channel quality indicator values from individual subscriber stations or greater than the rank 2 channel quality indicator values from several subscriber stations, then: Select one Single user multiple input, multiple output (multiple-output) rank-1 mode for data transmission; and Send of a data stream using the rank-1 vectors for beamforming corresponding to the subscriber station with the best rank 1 channel quality indicator value. The method of claim 9, further comprising: in an uplink transmission, receiving ranked 2 channel quality indicator values from the one or more subscriber stations; if a rank 2 channel quality indicator value is greater then as a rank 1 channel quality indicator value from a single subscriber station or greater than a rank 2 channel quality indicator value from multiple subscriber stations, then: selecting a single user multiple input, multiple output rank 2 mode for data transmission; and transmitting two data streams using the beamforming matrix for the subscriber station having the best ranked 2-channel quality indicator value. The method of claim 9, further comprising: in an uplink transmission Receive rank 2 channel quality indicator values from the one or more subscriber stations; if two or more subscriber stations have the best rank 2 channel quality indicator values have, then: Choose a multi-user multiple input, multiple output (multiple output) rank 2 mode for data transmission; and Send of two data streams using the beamforming matrices for the two or more subscriber stations with the best ranked 2 channel quality indicator values. Method according to claim 9, characterized in that that the channel quality indicator values at least partially on a singular value decomposition (singular value decomposition). Method according to claim 1, characterized in that that channel quality indicator values at least in part on an assumption of no interference between two or more streams based. Method according to claim 10, characterized in that that said receiving rank-1 channel quality indicator values from one or more subscriber stations and said receiving Rank 2 channel quality indicator values of the one or more subscriber stations in each subframe takes place. Method according to claim 10, characterized in that that said receiving rank-1 channel quality indicator values from one or more subscriber station (s) and said receiving of rank 2 channel quality indicator values from the one or more subscriber stations in each subframe at least in part on a Best M calculation takes place to feedback (feedback) overhead from the one or more users. Base station comprising: one with an antenna coupled radio frequency transceiver; and one with the radio frequency transceiver coupled baseband processor, wherein the baseband processor is capable to the: in an uplink transmission Receive rank-1 channel quality indicator values from one or more subscriber stations, the channel quality indicator values based at least in part on channel information; in a Uplink transmission Receiving two or more vectors from the one or more Subscriber station (s); Determine which of the one or more Subscriber station (s) has a best rank 1 channel quality indicator value; Determine a beamforming matrix based at least in part on the two or more vectors from the subscriber station with the best rank-1 channel quality indicator value were received; and broadcasting the beamforming matrix in a downlink transmission, the subscriber station with the best rank-1-channel quality indicator corresponds to the one or more subscriber stations. Base station according to claim 17, characterized the baseband processor is also capable of: in a Uplink transmission Receive rank 2 channel quality indicator values from the one or more subscribers' stations; if a rank 1 channel quality indicator value greater than the rank 2 channel quality indicator values from individual subscriber stations or greater than the rank 2 channel quality indicator values from multiple subscriber stations, then: selecting a single user multiple entry (multiple-input), multi-output (rank-1) mode for data transmission; and Sending a data stream using the rank-1 vectors for beamforming corresponding to the subscriber station with the best rank 1 channel quality indicator value. Base station according to claim 17, characterized the baseband processor is also capable of: in a Uplink transmission Receive rank 2 channel quality indicator values from the one or more subscriber stations; if a rank 2 channel quality indicator value greater than a rank 1 channel quality indicator value from a single subscriber station or greater than a rank 2 channel quality indicator value from several subscriber stations, then: Select one Single user multiple input, multiple output (multiple output) rank 2 mode for data transmission; and Send of two data streams using the beamforming matrix for the subscriber station with the best rank 2 channel quality indicator score. Base station according to claim 17, characterized the baseband processor is also capable of: in a Uplink transmission Receive rank 2 channel quality indicator values from the one or more subscriber stations; if two or more subscriber stations have the best rank 2 channel quality indicator values have, then: Choose a multi-user multiple input, multiple output (multiple output) rank 2 mode for data transmission; and Send of two data streams using the beamforming matrices for the two or more subscriber stations with the best ranked 2 channel quality indicator values.